Electrolyte for lithium secondary battery and lithium secondary battery comprising same

Abstract

The electrolyte for a lithium secondary battery comprises: a lithium salt; a solvent; and a functional additive, wherein the functional additive comprises naphthalen-1-yl sulfurofluoridate, represented by the following formula 1:

What is claimed is: 
     
       1. An electrolyte for a lithium secondary battery, the electrolyte comprising:
 a lithium salt; 
 a solvent; and 
 a functional additive, 
 wherein the functional additive comprises naphthalen-1-yl sulfurofluoridate, represented by the following formula 1: 
 
       
         
           
           
               
               
           
         
       
     
     
       2. The electrolyte of  claim 1 , wherein the naphthalen-1-yl sulfurofluoridate is added in an amount of 0.5-1.0 wt %, based on a total weight of the electrolyte. 
     
     
       3. The electrolyte of  claim 1 , wherein the functional additive further comprises lithium difluoro(oxalato)borate, represented by the following formula 2: 
       
         
           
           
               
               
           
         
       
     
     
       4. The electrolyte of  claim 3 , wherein the lithium difluoro(oxalato)borate is added in an amount of 0.5-1.0 wt %, based on a total weight of the electrolyte. 
     
     
       5. The electrolyte of  claim 1 , wherein the functional additive further comprises vinylene carbonate (VC). 
     
     
       6. The electrolyte of  claim 5 , wherein the vinylene carbonate (VC) is added in an amount of 0.5-3.0 wt %, based on a total weight of the electrolyte. 
     
     
       7. The electrolyte of  claim 1 , wherein the lithium salt is at least one compound selected from a group consisting of: LiPF 6 , LiBF 4 , LiClO 4 , LiCl, LiBr, LiI, LiB 10 Cl 10 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, LiN(SO 2 C 2 F 5 ) 2 , Li(CF 3 SO 2 ) 2 N, LiCF 4 F 9 SO 3 , LiB(C 6 Hs) 4 , Li(SO 2 F) 2 N(LiFSI), and (CF 3 SO 2 ) 2 NLi. 
     
     
       8. The electrolyte of  claim 1 , wherein the solvent is at least one substance selected from a group consisting of: a carbonate-based solvent, an ester-based solvent, an ether-based solvent, and a ketone-based solvent. 
     
     
       9. A lithium secondary battery, comprising an electrolyte comprised of:
 a lithium salt; 
 a solvent; and 
 a functional additive, wherein the functional additive comprises naphthalen-1-yl sulfurofluoridate, represented by the following formula 1: 
 
       
         
           
           
               
               
           
         
       
     
     
       10. The lithium secondary battery of  claim 9 , further comprising:
 a positive electrode containing a positive electrode active material composed of Ni, Co, and Mn; 
 a negative electrode containing at least one negative electrode active material selected from a carbon (C)-based material and silicon (Si)-based material; and 
 a separator interposed between the positive electrode and the negative electrode. 
 
     
     
       11. The lithium secondary battery of  claim 10 , wherein the positive electrode contains Ni at a content of 80 wt % or more. 
     
     
       12. The lithium secondary battery of  claim 9 , wherein the naphthalen-1-yl sulfurofluoridate is added in an amount of 0.5-1.0 wt %, based on a total weight of the electrolyte. 
     
     
       13. The lithium secondary battery of  claim 9 , wherein the functional additive further comprises lithium difluoro(oxalato)borate, represented by the following formula 2: 
       
         
           
           
               
               
           
         
       
     
     
       14. The lithium secondary battery of  claim 13 , wherein the lithium difluoro(oxalato)borate is added in an amount of 0.5-1.0 wt %, based on a total weight of the electrolyte. 
     
     
       15. The lithium secondary battery of  claim 9 , wherein the functional additive further comprises vinylene carbonate (VC). 
     
     
       16. The lithium secondary battery of  claim 15 , wherein the vinylene carbonate (VC) is added in an amount of 0.5-3.0 wt %, based on a total weight of the electrolyte. 
     
     
       17. The lithium secondary battery of  claim 9 , wherein the lithium salt is at least one compound selected from a group consisting of: LiPF 6 , LiBF 4 , LiClO 4 , LiCl, LiBr, LiI, LiB 10 Cl 10 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, LiN(SO 2 C 2 F 5 ) 2 , Li(CF 3 SO 2 ) 2 N, LiCF 4 F 9 SO 3 , LiB(C 6 Hs) 4 , Li(SO 2 F) 2 N(LiFSI), and (CF 3 SO 2 ) 2 NLi. 
     
     
       18. The lithium secondary battery of  claim 9 , wherein the solvent is at least one substance selected from a group consisting of: a carbonate-based solvent, an ester-based solvent, an ether-based solvent, and a ketone-based solvent.